Mechanical pencil



March 2, 1937 w. R. CUTHBERT Er AL 2,072,711

, MECHANICAL PENCIL Filed Aug'. :51, 1955 Patented Mar. 2, 1937 PATENT OFFICE MECHANICAL PENCIL William R. Cuthbert and William H. Lindemon, Fort Madison, Iowa, assignors to W. A. Sheaifer Pen Company, Fort Madison, Iowa, a corporation of Delaware Application August 31, 1935, Serial No. 38,672

5 Claims.

This invention relates to a writing instrument and has special reference to a device employing mechanism for feeding individual leads beyond the end of a barrel thereof for use in Writing and for retracting the leads for storage within the barrel.

More particularly, this invention has reference to a writing instrument in which a spirally slotted sleeve is rotatably mounted in a guide tube for operating lead engaging means to feed'the lead,

there being a detachable cap carried by the casingv with means extending therefrom through a support for the guide tube to impart rotation from the cap to the sleeve.

The present invention contemplates the cen tering of the-guide tube and spirally slotted sleeve by means of a spider adjacent the-end of the instrument on which, the cap is detachably mounted to permit. an unobstructed chamber for the storageof extra leads. is employed, as. an ,operating headfor the spirally slotted sleeve to feed lead throughthe medium of. a leadclutch, a pin extending from the cap through l the spider for engagement with the` Further, this invention contemplates anl overriding movement between the operatingA head.

sleeve.

or cap` and the spirally slotted sleeve to prevent jammingof the mechanism at vthe limit of.

movement ofthe operating, members in either direction.

Other objects and advantages will hereinafter be more particularly pointed out and for a more complete understanding ofthe characteristic features of'this invention, reference may now be had to the' following description when taken together with the accompanying drawing, in which latter:

Figure 1vis a vertical central sectional view of a-writing instrument embodying the features of this invention;

Fig. 2 is an enlarged View similar to'Fig. 1 with an intermediate portion broken away;

Fig.`3 is a sectional viewtaken. on the line 33 of. Fig. 2; .y

I Fig. 4 isa sectionalview takenon the line 4-4 of Fig. 2;

Fig. 5. is a sectional'view taken on the line 5-5 of Fig. 2;

Fig. 6 is a sectional View taken on the line iofFig. 2;

Fig. 'l is a perspective view of acenteringbushing.; and.

Fig. 8 is an enlarged fragmentary perspective View of the endportion of a spirally slottedsleeve.

Referring now more particularly to the draw- The detachable capV (CL 1Z0-18) ing, the pencil embodying the present invention is illustrated therein and comprises an elongated casing Ill which is tubular in form and preferably formed of a plastic composition such, for example, as is known to the trade as Radite, although, of course, any suitable rigid material may be satisfactorily employed.

The writing end portion of the barrel is provided with a conical-shaped metal tube II having an axial opening I2 of such size and cross section as to permit a pencil lead crayon to have a free reciprocal movement therethrough, although it is restricted enough to stabilize the lead and prevent wobbling thereof. The opening I2 communicates with an enlarged opening toward the base of the cone to receive a filler piece ifi for the purpose of preventing the breaking of the lead, the filler piece, of course, having a bore disposed substantially coaxially with the opening I2. The base of the cone-shaped metal tube has a collar I0.- extending therefrom, the outer diameter of the collar being of reduced cross section from that of the base of the cone and having longitudinally extending corrugations for effecting a snug drive fit with an enlarged bore portion I 5 at the end of the casing I0.

The upper end of the casing I0 is provided with a plurality of longitudinally extending slots I6 and a peripheral groove II approximately midway of the length of the slots. This construction permits of a detachable engagement of a cylindrical cap I8 with the end of the pencil, the cap telescoping the end of the barrel and having a peripheral restriction or indentation I 9 for engaging the peripheral groove Il of the casing. In telescoping the cylindrical cap over the end of the casing, the indentation forces a reduction in diameter of the end of the casing which is permitted by reason of the longitudinally extending grooves IS until the groove II and indentation I 9 register with a snap engagement. Thus the cap I3 or operating member is detachably carried by the casing.

The detachable cap I8 carries an exposed eraser 20, the eraser being formed preferably of a cylindrical piece of rubber having a band 2| fixed at an intermediate portion thereof and the very simple in construction and provides a very ecient use of the rubber portion thereof, since upon using the exposed end of the rubber, the latter may be reversed in the collar 22, whereby the other end of the rubber may be exposed for use.

The cap further provides for the positioning of the operating means for the lead feeding mechanism, there being a cup-shaped member fixedly secured within the cylindrical cap i8, the base of the cup-shaped member 25 having a pin 26 secured thereto in any usual manner, the pin preferably extending through an aperture in the base and being limited in its movement in one direction by a shoulder in the pin and being upset to limit movement in the other direction. The extending portion of the pin 26 is of circular cross section for a portion of its length and is journaled in a collar 2l of a spider, the latter having legs 28 for engaging the bore of the casing. A reduced extensionZS from the circular cross section of the pin 26 is of polygonal cross section and is preferably four-sided.

The mechanism for repelling and retracting the pencil lead comprises a' longitudinally grooved guide tube 33 which is fixed against rotation relative to the casing and a spirally slotted sleeve 3| which is rotatably mounted within the tube 33. The diameter of the guide tube is substantially less than the internal bore of the casing and the tube is held in a centrally spaced relation with the bore of the casing at the detachable cap end by means of telescopically engaging the collar 2 of the spider and at the other end by a slotted bushing 32. The slotted bushing 32 is held in a fixed relation with the inner bore of the collar I3, the guide tube 3|) having a forced engagement with the bore of the bushing 32 and being limited by a shoulder provided by a reduced opening of the bore, which latter is substantially the diameter of the bore of the ller piece I3.

The guide tube is held in a xed relation against rotary movement, the raised portion 33 forming the longitudinal groove of the guide tube tting snugly within the slot 33 of the slotted bushing 32. The guide tube is held against longitudinal movement in one direction by the bushing 32 and in the other direction by the spider. The spider, of course, permits the entrance of extra leads into the space between the guide tube and the inner bore of the casing, an unobstructed passage being had between the legs 28 of the spider.

The spirally slotted sleeve 3| is permitted to rotate Within the guide tube, although it is held in position against longitudinal movement by means of a collar 35 against which one endl of the sleeve engages and the restricted end of the bushing 32 at the other end of the sleeve. The collar 35 is, in turn, held against displacement by a constriction 35a in the guide tube 30.

Within the sleeve 30 is a lead socket 36, the outer end of which clutches the inner end' of the stick of lead. A plunger 31 extends through the guide tube likewise preventing rotation of the plunger 3l through the medium of finger 33.

The screw sleeve 3| is rotatable with respect to the guide tube 30. A rotation of the screw sleeve compels the fingers 38 and 33 to ride in a longitudinal direction to propel or retract the pencil lead, the plunger operating to eject the lead after the lead socket has been urged to the limit of its forward movement. The limit of retraction of the lead socket is determined by a pinched portion 33a of the groove of the guide tube, the opening of the groove being constricted and acting as a stop against which the nger 38 abuts.

Referring no-w more particularly to Fig. 8, it will be noted that the spirally slotted sleeve 3| is squared at the detachable cap end of the barrel, or is of polygonal cross section, although, of course, it is to be understood that any noncircular cross section would be readily adaptable for the purpose to which it is intended. However, forpurposes of illustration, the cross section is shown as being square. Further, the bore of the sleeve at the outerr end thereof is of such a diameter as to snugly engage the periphery ofthe squared end portion 29 of the pin 26. In any event, the cross section of the end of the pin 23 should conform to the bore of the end of the sleeve 3|.

It is to be noted that with the above construction, the sleeve 3| is spirally slotted to the extreme outer end thereof and that the slot extends from that end in a counter-clockwise direction. When the sleeve is rotated Within the guide tube to a position such that the ngers 38 and 39 are operated to their limits, the resiliency of the metal of the sleeve will permit an overriding movement so as to prevent jamming of the mechanism. It will readily be apparent that Vthe solid rod 29 of square cross-section may be rotated within the bore of the sleeve 3| at the squaredend thereof since the sleeve is spirally slotted and will expand across the diameter thereof when manually forced after the limits of movement of the lead clutch has been obtained. It is also to be noted that the detachable member is employed as an operating member to feed lead through the medium of the lead clutch, the cap having apin which extends through the rear end of the external mechanism. The Yspider is essential for providing an unobstructed chamber for the storage of extra leads.

While but a single embodiment of this inven-Y tion is herein shown and described, it is to be understood that various modications thereof may be apparent to those skilled in the art without departing from the spirit and scope of this invention and, therefore, the same is only to be limited by the scope of the prior art and the appended claims.

We claim:

1. A writing instrument of the character described comprising a casing, a longitudinally grooved guide tube xed against rotation relative to and within said casing, a spirally slotted sleeve rotatably mounted within said tube, lead engaging means within said sleeve forV engagement with both the groove and the spiral slot for feeding the lead longitudinally upon relative rotatable movement between the tube and sleeve, a rotatable cap detachably carried by said casing, and a pin of polygonal cross section carried by said detachable cap, said sleeve having a polygonal end opening for slidably receiving said pin into an operative relation in which rotation of said cap Will impart rotation to said sleeve.

2. A Writing instrument of the character described comprising a casing, a longitudinally grooved guide tube xed against rotation relative to and Within said casing, a spirally slotted sleeve rotatably mounted Within said tube, lead engaging means within said sleeve for engagement with both the groove and the spiral slot for feeding the lead longitudinally upon relative rotatable movement between the tube and sleeve, a rotatable cap detachably carried by said casing, and a pin of polygonal cross section carried by said detachable cap, the spiral slot of said sleeve being extended to the extreme end thereof and that end being formed into polygonal cross section for receiving said pin in an operative relation for imparting rotation from said cap to said sleeve.

3. A writing instrument of the character described comprising a casing, a longitudinally grooved guide tube fixed against rotation relative to and within said casing, a spirally slotted sleeve rotatably mounted Within said tube, lead engaging means within said sleeve for engagement with both the groove and the spiral slot for feeding the lead longitudinally upon relative rotatable movement between the tube and sleeve, a cylindrical cap for telescoping one end of said casing, said cap having a peripheral indentation for engaging a peripheral groove of said casing to permit relative rotatable movement and to prevent relative longitudinal movement except detachment by force, and a pin of polygonal cross section carried by said detachable cap, said sleeve having a polygonal end opening for receiving said pin in an operative relation for imparting rotation from said cap to said sleeve.

4. A Writing instrument of the character described comprising a casing, a longitudinally grooved guide tube of substantially smaller diameter than the diameter of the bore of said casing, a spider having legs thereof frictionally engaging the bore of said casing and a reduced collar for engaging and for centering one end of said tube, a spirally slotted sleeve rotatably mounted within said tube, lead engaging means within said sleeve for engagement with both the groove and the spiral slot for feeding the lead longitudinally upon relative movement between the tube and sleeve, a rotatable cap detachably carried by said casing, and means carried by said cap extending through said reduced collar for engagement with said sleeve for imparting rotation from said cap to said sleeve.

5. A Writing instrument of the character described comprising a casing, a longitudinally grooved guide tube of substantially smaller diameter than the diameter of the bore of said casing, a spider having legs thereof frictionally engaging the bore of said casing and a reduced collar for engaging and for centering one end of said tube, a spirally slotted sleeve rotatably mounted within said tube, lead engaging means Within said sleeve for engagement with both the groove and the spiral slot for feeding the lead longitudinally upon relative movement between the tube and sleeve, a rotatable cap detachably carried by said casing, and a pin carried by said cap having rotatable engagement with the bore of said reduced collar and extending there through for engagement with said sleeve for imparting rotation from said cap to said sleeve.

WILLIAM R. CUTHBERT. WILLIAM H. LINDEMON. 

